Taking 17th-century philosopher and mathematician Blaise Pascal’s reference to an “infinite sphere, whose center is everywhere and whose circumference is nowhere” as a starting point, String Quartet No. 4: The Infinite Sphere taps the potentials of Classical circular forms and techniques – in particular rondo form and canonical rounds – to explore the expressive tension between the coherence of the sphere and the chaos of infinity. The result is a two-movement rondo structure (ABAC-ABA) in which all of the surface details reflect the wheels-within-wheels form:

String Quartet No. 4: The Infinite Sphere, running twenty-two minutes, was commissioned by the Daedalus Quartet and the Thomas S. Kenan Institute for the Arts. It was premiered by the Daedalus String Quartet at Wolf Trap in January 2010, with further performances in Philadelphia, Winston-Salem and New York.

“It grabs one’s attention from the very beginning with an infectiously rhythmic
canon, and it changes character often before it closes with wit after 22
minutes. One high point that deserves mention is a slow section in I for string
harmonics—a breathtaking, perhaps mournful passage whose beauty will turn
heads.”

- American Record Guide

“There was a lot to enjoy, not least the pulsating repetition of the rock bacchanale sections and the buzzing tremolos of the fervent fifth movement.”

- Charles T. Downey, ionarts

“Dillon's "Quartet No. 4: The Infinite Sphere" is a work of jewel-like craftsmanship, in arch form, consisting of seven movements alternating between rounds and rondos. The tonal language is not dissonant, but not conservative either; Dillon seems to reach across several centuries for inspiration, somewhat like Benjamin Britten. The centerpiece -- a "circular fugue" -- had each new voice enter at a faster tempo than the previous, and indeed, Dillon's control of time was a conspicuously imaginative element throughout. It is a fine addition to the repertoire, rendered with great skill by its dedicatees.”